According to this talk, trade is ten times as old as farming. The speaker points out that humanity can do things that it doesn't understand. That reminded me of the Eureka robot which was in the news last year. The speaker also made the point that individual IQ doesn't matter much anymore—the existence of exchange is far more important. For example, no single person knows how to make a pencil, and no single person knows how to make a computer mouse—both of those items are created because different people specialize in different tasks along the production chain and exchange with each other.